#查询数据库连接
show full  processlist;
show status like '%Max_used_connections%';
show status like '%Threads_connected%';#当前连接数
show status like '%table_lock%';#表锁定
show status like 'innodb_row_lock%';#行锁定
show status like '%qcache%'; #查询缓存情况
show variables like "%query_cache%";
SHOW STATUS LIKE 'Qcache%'; 
show variables like "%binlog%";
show status like 'Aborted_clients';#由于客户没有正确关闭连接已经死掉，已经放弃的连接数量
show variables like '%max_connections%';
show variables like '%timeout%';
show variables like 'log_%'; #查看日志是否启动